Catheter-based devices that deploy expandable structures into interior body regions are well known. These structures are typically introduced through a body lumen or vessel in a collapsed, low profile condition. Once at or near the targeted body region, the structures are expanded in situ into an enlarged condition to make contact with tissue. The structures can carry operative elements that, when in contact with tissue, perform a therapeutic or diagnostic function. They can, for example, deliver energy to ablate targeted tissue in the region.
Some of these structures can be expanded by inflation by delivery of fluid into the interior of the structure. It is desirable to control the amount of inflation, so as not to over-inflate the structures. Over-inflation can lead to damage of the structure, or unintended trauma or damage to nearby tissue.
With structures that are expanded in situ, it is also desirable to ascertain whether the structure actually is in contact with the targeted tissue region. Absent such contact, the desired therapeutic or diagnostic outcome may not be achieved.